Discharge device



. July 14, 1936. H. J. SPANNER DISCHARGE DEVICE Filed Nov. 3, 1934 INVENTOR ///i/V f A/V/V I Patented July 14, 1936 UNITED STATES PATENT orrlcs amass mscmca mrvrca Hans J. Spanner, Berlin, Germany I Application November 3, 1934, Serial No. 151,:91 1 claims. (01. 110-124) This invention relates to electrical discharge devices and more especially to those oi the high pressure metal vapor filled type.

It is an object oi this invention to make a suitable discharge tube in which an arc of sumcient length and of high current load and brilliancy can be started and maintained between non-contacting electrodes, and which will have a very long life.

m In my copending application, Serial No. 558,143, filed August 19, 1931, or which this application is a continuation in part, I have disclosed and claimed such high pressure discharge devices and various improvements therein by which great ad- 15 vantages and economies of operation and/or of manufacture are attained.

As set forth in my said application the creation and maintenance of higher vapor pressure within the device is important and accordingly 9 I have disclosed and claimed therein various features by which the walls oi the luminous vessel may be maintained during operationeven at the coldest part at a temperature suiilcient to insure the desired high pressure, above 180 C.;

and I especially pointed out that the pole rooms .should be made very small and/or by capsulating the ends of the vessel with some heat insulating material, e. g., asbestos. a reflecting metal coating, etc., and/or by surrounding vessels, e. g.,

0 simple tubes or Dewar vessels, permeable to light,

the heat may be concentrated or held in the pole rooms about the electrodes to prevent objectionable condensation of mercury therein.

With the electrodes thus positioned close to 35 the walls of the vessel the lead-in wires, it they should pass directly from strongly heated part or the electrode to the nearest part oi the vessel wall would be heated to too high a temperature where they pass through the walls.

40 According to the present inventions, therefore, the lead-in wires may be brought through the vessel wall at a point more distant than the nearest point from the intensely heated portion where the arc strikes the electrode, and especially may be made of greater length than the shortest distance between the electrode and the point at which the lead-in passes through the vessel wall. Such extra length of the lead-in wire permits it to dissipate the heat conducted from the electrode so that where it enters the vessel wall it may approximate the temperature of the wall. Thus overheating oi the vessel adiacent the wire may be avoided and at the same time as the desired high temperature may be maintained in the space behind the electrode by heat dissipated from said wire.

Conduction or heat along the lead-in wire to the point at which it passes through the vessel wall may also be limited by using the smallest 5 size wire permissible in view oi the weight of the electrode and the current flowing through it.

In a high pressure tube it is important that the thermionic electrodes be so arranged or oi such type that they do not seriously shield the 10 space behind them irom the heat of the discharge or else they must assume a temperature during operation such that they themselves heat this space to a temperature which will prevent objectionable condensation of the vapor filling.

In the accompanying drawing I have shown one embodiment of my invention for the purpose of illustrating the same but without limiting it thereto.

Figure 1 is a view in elevation of a lamp embodying my invention.

Figure 2 is a view in perspective on an enlarged scale of one electrode and its lead-in wire.

Figure 3 is a view similar to Figure 2, but showing a modified electrode support. 5

Figure 4 is a fragmentary view of one end oi' a tube having a spiral wire electrode and two lead-in wires, the remainder thereoi being substantially as shown in Figure 1.

Figure 5 is a fragmentary view similar to Figure 4 but showing a sell-heated electrode, as in Figure 1, with an auxiliary electrode.

A suitable form of thermionic electrode for tubes of the type specified is one which consists of a metal ring open on one side, and the electrode body proper interposed in it with the ends of the ring welded or aflixed by any other suit able means to the activated body. The lead-in wire is so curved that it permits the electrode body to be mounted close enough to the wall to heat it sumciently, as described above, and to properly locate it in the pole room so that it will heat the walls thereof substantially evenly throughout to the desired temperature.

Such an electrode and its support consisting of the lead-in wire and the ring is shown in Figures 1 and 2. Numerous other forms of electrodes may be used with my invention, e. g., spiral or twisted wires, closely arranged laminae, telescoped cylinders, ribbons, etc. The particular structure 0! the electrode is not essential to the present invention.

, Referring to Figures 1 and 2.

In the drawing the luminous tube comprises,

a substantially cylindrical internal envelope 0! 66 glass I, having substantially spherical ends 2, into which are sealed the lead-in .wires 3. To the lead 3, is spot-welded the metal ring it, which is open on one side, and the electrode body proper It, is interposed therein so that the ends of the electrode are firmly attached to the ends of the ring by welding or some other suitable means.

This electrode may consist, for example. of thin wires of nickel, cobalt chromium, copper, or similar metals or mixtures, or of tungsten, molybdenum, or tantalum, twisted or spiralled and the resulting body filled with refractory activating material, e. g., with a filling material combining barium oxide or other suitable compounds of strongly electro-positive metals with zirconium oxide or other refractory heat and electrical insulating materials which do not spoil the emissive quality of the electro positive material and, preferably, with magnesium or calcium oxide; all as more fully set forth in my copending application. Since the arc strikes at the nearest part of the electrode which is sufilciently activated, the remainder of this electrode body and especially the ends of the spirals serve in eflect like the ring l3 as a part of the electrode supp rt. The lead-in wire 6 is so bent that the electrode may be mounted very close to the rear wall so as to prevent condensation places thereon. This bend causes the length of the lead-in to be greater than the smallest distance of the electrode from the wall. Further increasing this result, the lead-in wire is connected to the opposite side of the ring B from the electrode I I, thus making the ring a part of the electrode support.

If a smaller type of electrode were used then the pole vessel might be made proportionally smaller so as to maintain this close proximity of the electrode and the wall which prevents dead spaces. In order further to promote the heating of the ends of the tube they may be covered with caps i5, of heat concentrating or heat insulating material, e. g., as shown in section in Figure 5.

The inner envelope I, is arranged within an outer envelope. 1, and may be secured to a lamp base I! of standard form at one end. The leads 9 and III of the discharge tube are connected to the base as shown, the center lead I being of fairly heavy wire attached to the lead-in wire 3 under a glass collar and being the principal support of the inner envelope. Wires II are placed around the inner envelope at the constrictions Ii, which are preferably formed in the tube to prevent the blackening from extending to the light tube proper, three twisted loops ll located at approximately equidistant points around its circumference locate the lamp centrally in the outer jacket I. A spiral spring I8 is placed around the upper lead-in seal to hold the discharge tube in position under a slight tension longitudinally in the outer Jacket and thus to prevent vibration of the inner envelope. In this case the outer envelope acts chiefly as a protective jacket and it may be unevacuated or it may be evacuated so as to form with the envelope i, a Dewar vessel.

The internal envelope contains enough mercury to give a pressure of about one atmosphere when operating, together with a few millimeters of argon to facilitate starting.

A wire I0 which may be one of the leads to the upper electrode is carried along the outside of the inner envelope to a point near the other electrode. At this point near the other electrode it may be connected to the wire ring l1, or to any other form such as a ring or cylinder to broaden its area effectively. In addition or alternatively, an auxiliary electrode 2i, as shown in Figure 5, may be put inside the tube near 5 one of the main electrodes and connected to the other main electrode by a high resistance in a known manner. The use of the outer envelope with these forms of starting arrangement is particularly convenient, for in addition to its heat re- 1 taining function, it permits live conductors to be 7 run along the outside of the discharge tube proper, without any danger that they may he accidentally touched.

Figures 3 and 4 show other types of electrodes 15 and supports which may be used instead of those shown in Figures 1 and 2. In Figure 3 a disk 13a replaces the ring l3. Being slotted across its center it is effective as a ring conductor plication Serial No. 387,986 filedAugust 23, 1929.

This electrode is activated with a refractory 'filling material as already described herein and in my said prior applications. It should be understood that the above is given with a view to explaining my invention and enabling others to apply it under various conditions, and is not intended to be exhaustive; on the contrary, it is contemplated that numerous changes and variations may be made within the scope of my invention.

What I claim is:--

1. A luminous electric discharge device provided with a filling including a vaporizable metal in amount adapted to produce a high pressure are discharge comprising a tubulaur envelope with rounded ends, solid activated arc electrodes adapted to carry an arc current sufilcient to maintain the high pressure discharge, electrode supports distorted along the length thereof so as to bring said electrodes close to the end walls of said envelope, and a source of current adapted to supply energysuflicient to produce the high pressure discharge by vaporization of said metal..

2. A luminous electric discharge device provided with a filling including a vaporizable metal in amount adapted to produce a high pressure" are discharge comprising a tubular envelope with rounded ends, solid activated arc electrodes}? adapted to carry anarc current suiiicient to maintain the high pressure discharge, an electrode supportsfor each electrode comprising a lead-in wire sealed through'the wall of the en- 65 velcpe and a member on which the electrode ismounted which is attached to the lead-in wire at a point substantially spaced from the electrode and which has greater radiation area between the electrodes and said points of attachment to the lead-in than would a mere continuation of the lead-in wire directly to the electrode, distorted along the length thereof so as to bring said electrodes close to the end walls of said envelope. an a source of current adapted to sup- 1s ply energy'suflicient to produce the high pressure discharge by vaporization of said metal.

3. A luminous electric discharge device provided with a filling including a vaporizable metal in amount adapted to produce a high pressure are discharge comprising a tubular envelope with rounded ends, solid activated arc electrodes adapted to carry an arc current sufiicient to maintain the high pressure discharge, and electrode support wires distorted along the length thereof so as to bring said electrodes close to said ends of said envelope and said support wires extending through the wall of said envelopes at a part other than that least distant from said electrodes, and a source of current adapted to supply energy suflicient to produce the high pressure discharge by vaporization of said metal.

4. A luminous electric discharge device provided with a filling including a vaporizable metal in amount adapted to produce a high pressure are discharge comprising a. tubular envelope with rounded ends, solid activated are electrodes comprising a spiral of refractory metal, a filling therein of refractory electron emitting material, and electrode supports comprising in part at least, a portion of said spiral, and a source 01' current adapted to supply energy suflicient to produce the high pressure discharge by vaporization of said metal.

5. A luminous electric discharge device provided with a filling including a vaporizable metal in amount adapted to produce a high pressure are discharge comprising a tubular envelope with rounded ends, solid activated arc electrodes adapted to carry an arc current suiiicient to maintain the high pressure discharge, electrode support wires distorted along the length thereof, a thermally insulating jacket enclosing said envelope, and means for supporting said envelope from said jacket, and a source of current adapted to supply energy suiiflcient to produce the high pressure discharge by vaporization of said metal. 6. A luminous electric discharge device provided with a filling including a vaporizable metal in amount adapted to produce a high pressure arc discharge comprising a tubular envelope with rounded ends, solid activated arc electrodes adapted to carry an arc current sufllcient to maintain the high pressure discharge, electrode support wires distorted along the length thereof and a heat storing cap on an end of said envelope, and a source of current adapted to supply energy suificient to produce the high pressure discharge by vaporization of said metal.

7. A luminous electric discharge device provided with a filling including a vaporizable metal in amount adapted to produce a high pressure" are discharge comprising a tubular envelope with rounded ends, solid activated arc electrodes adapted to carry an arc current suflicient to maintain the high pressure discharge, electrode support wires distorted along the length thereof and means for facilitating the starting of the'discharge comprising a conducting member arranged along and around the exterior of said envelope and connected to one electrode, and a source of current adapted to supply energy surficient to produce the high pressure discharge by vaporization of said metal.

- HANS J. SPANNER.

CERTI ICA O CQ EQTION,.

Patent No. 2,047,390.' July 14, less.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 2, second column, line 47, claim 1, for "tubulaur" read tubular; line 75, claim 2, for "an" read and; page 3, first column, line 22, claim 4, after "electrodes" insert the words adapted to carry an arc current sufficient to maintain the high pressure discharge; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 29th day of September, A. D. 1956.

Henry Van Arsdale Acting Commissioner of Patents. 

